Sorry, but I don't see that happening since that would involve backporting Qt 5.3 as that is what upstream advises to use with Plasma 5, and backporting Qt5 is a huge hassle and a even bigger hassle to maintain the packages for the lifetime of the 14.04 release. However, fear not! You can try out Neon 5 which is built for Trusty! See https://techbase.kde.org/Getting_Started/Using_Project_Neon_...